Cutting tools for drilling concrete, aggregate, masonry or the like materials

ABSTRACT

A cutting tool ( 500 ) has a longitudinally extending shaft portion ( 588 ) with a chucking part ( 509 ) and a cutting head ( 506 ). A pressed powder cutting insert ( 518 ) with a cutting edge ( 520 ) is on the cutting head ( 506 ). The cutting edge ( 520 ) includes at least one cutting portion. A rake surface ( 524 ) is formed adjacent to at least one of the cutting portions ( 520 ) with the rake face ( 524 ) being at a rake angle from about 0° to 10°. A clearance face ( 526 ) is formed adjacent to the at least one cutting portion opposite the rake face ( 524 ). The clearance face ( 526 ) is at a clearance angle from about 10° to 50°. An edge radius ( 540 ) between the rake face ( 524 ) and the clearance face ( 526 ) is at a radius of from about 0.0015 to about 0.004 inch. The edge radius  540  is formed during pressing of the powder to form the insert, thus, enabling the insert to be directly braised into the cutting head ( 506 ).

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 08/354,349, filed Dec. 12, 1994, entitled CUTTINGTOOLS FOR DRILLING CONCRETE, AGGREGATE, MASONRY OR THE LIKE MATERIALS,the specification and drawings of which are expressly incorporated byreference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to cutting tools or drill bits, andmore particularly, to cutting tools which are used in hammering,percussive, or rotary boring or drilling applications in concrete,aggregate, masonry or the like material.

[0003] When drilling concrete, aggregate or the like materials,generally three different types of cutting tools or bits are used. Thesebits can be defined as hammer bits, percussive bits, and rotary masonrybits. In a true hammer bit, the bit is placed into a driver whichincludes a hammer which is sequentially and repetitiously moved towardand away from the bit. This hammering action hammers the bit. While thebit is being hammered, the bit continues to either passively or activelyrotate. Thus, this type of cutting would be synonymous with using achisel and hitting it with a hammer. Also, the driver may include arotational feature where the bit is hammered and actively rotated.

[0004] In percussive drilling, the drive includes a chuck which isassociated with stepping cam surfaces on gears which are rotated and, atthe same time, moved up and down within the driver. Thus, the entirechuck mechanism rotates and moves up and down during the cuttingprocess.

[0005] A rotary masonry bit is positioned into a driver which providesonly a rotary movement. Thus, the rotary masonry bit does not move upand down and just rotates to cut at the concrete or aggregate.

[0006] Cutting tools in these three fields require different parametersfor each type of application. In hammer and percussive bits, whichutilize a chiseling action, the tip cutting angle, which provides tipstrength, debris elimination and a cutting or rake face are a primaryconcern. Likewise, in rotary masonry drilling, which uses purely rotarymovement, the cutting or rake face, debris clean out and cutting angleare also of primary importance. However, all of these elements areinterrelated to provide an optimum cutting tool or drill bit to drillconcrete, aggregate and the like materials.

[0007] Existing hammer and percussive cutting tools ordinarily includecarbide insert tips with cutting edges which have large obtuse includedangles as well as a negative rake face at large acute angles. Thus, thetip has been utilized to chisel and rotate to drill or bore into theconcrete material. The rotary masonry bits ordinarily use a rake face onthe bit so that when it is rotated, it will bore through the concretematerial.

[0008] Further, when the carbide tips are formed, the carbide powder islaterally pressed into a mold to form the tip. This tip is inserteddirectly and welded or brazed onto a tool shank. Thus, this is the artaccepted way to form current design tools or bits.

SUMMARY OF THE INVENTION

[0009] Accordingly, it is an object of the present invention to providethe art with a cutting tool or bit which will reduce the time to drillholes into concrete, aggregate or the like material and improve thequality of the hole. The present invention has an improved cutting tipwith a rake face which is slightly negative, zero or positive. The tipcutting angle, which is the angle between the rake face and clearanceface, is smaller than current designs to provide better chiselingaction. Also, the insert can be formed from pressed powder and maintainthe desired tip cutting angle. The debris recess of the presentinvention rapidly ejects debris from the tip into the helical flutes. Arake face on the cutting tools increases cutting action during rotationof the cutting tools in the hole.

[0010] Also, in accordance with one aspect of the present invention, theformed carbide tip is worked, contrary to conventional teaching, toincrease performance of the tip in drilling concrete, aggregate, masonryor the like material. The term “works” means the tip is ground orotherwise to sharpen or form a sharpened cutting edge on the tool. Inanother aspect, it has been found that the insert can be pressedpowdered metal and still maintain the desired tip cutting angle.Further, in a ball head design tool, the present invention has a largeregress space. Egress space is defined as the open volume through whichdebris may pass on its way from being created to the flute of the bit toenable faster removal of debris.

[0011] In accordance with a second aspect of the invention, a cuttingtool comprises a longitudinally extending shank portion which defines alongitudinal axis and two ends. One end has a chucking part and theother end has a cutting head. A cutting edge is on the cutting head andincludes at least one cutting portion. A rake surface is formed adjacentto at least one of the cutting portions. Also, a clearance face isformed adjacent to the at least one cutting portion opposite the rakeface. An edge radius is formed between the rake face and the clearanceface and has a radius from about 0.0005 to 0.001 inch. Likewise, amethod of boring a hole in concrete, aggregate or the like material isdisclosed using the above cutting tool. The cutting edge of the cuttingtool is placed in contact with the concrete, aggregate or the likematerial. The cutting tool is rotated to bore the material. Due to theboring, a hole is formed in the material. Alternately, instead ofrotating the tool, the tool may be impacted to chisel away the materialto form the hole. optionally both boring and impacting may be conductedsimultaneously.

[0012] In accordance with a third aspect of the invention, a cuttingtool includes a longitudinally extending shank with a chucking end and acutting head. A cutting edge is formed in the cutting head with at leastone cutting edge portion. A rake surface is formed adjacent to at leastone of the cutting portions with the rake face at an angle of from about−10° to 10°. A method for boring a hole in concrete, aggregate or thelike material is disclosed using the above cutting tool. The cuttingedge of the cutting tool is placed in contact with the material. Thecutting tool is rotated to bore the material. Due to the boring, a holeis formed in the material. Alternatively, instead of rotating the tool,the tool may be impacted to chisel away the material to form the hole.Optionally both boring and impacting may be conducted simultaneously.

[0013] In accordance with a fourth aspect of the invention, a cuttingtool includes a shank portion with a chucking end and a cutting head.The head includes a cutting edge with at least one cutting edge portion.A rake surface is formed adjacent to at least one cutting edge portion.Additionally, a clearance surface, is formed adjacent to the at leastone cutting portion opposite the rake face. One or both the rake surfaceand clearance surface are worked to form a sharpened edge radius. Amethod of boring a hole in concrete, aggregate or the like material isdisclosed using the cutting tool. The cutting edge of the cutting toolis placed in contact with the material. The cutting tool is rotated tobore the material. Due to the boring, a hole is formed in the material.Alternatively, instead of rotating the tool, the tool may be impacted tochisel away the material to form the hole. Optionally both boring andimpacting may be conducted simultaneously.

[0014] In accordance with a fifth aspect of the invention, a cuttingtool comprises a longitudinal shank with a chucking part at one end anda cutting head at the other end. The cutting head includes a cuttingedge with at least one cutting edge portion. A rake surface is formedadjacent to the at least one of the cutting edge portion. A primaryegress surface is formed immediately adjacent the rake surface such thatthe rake surface, and primary egress surface define a new egress path. Amethod for boring a hole in concrete aggregate or the like material isdisclosed using the above cutting tool. The cutting edge of the cuttingtool is placed in contact with the material. The cutting tool is rotatedto bore the material. Due to the boring, a hole is formed in thematerial. Alternatively, instead of rotating the tool, the tool may beimpacted to chisel away the material to form the hole. Optionally bothboring and impacting may be conducted simultaneously.

[0015] In accordance with a sixth aspect of the invention, a cuttingtool comprises a longitudinally extending shank with a chucking part atone end and a cutting head at the other end. The cutting head includes acutting edge with at least one cutting edge portion. A rake surface isformed adjacent to the at least one cutting edge portion. The rakesurface includes a worked portion which extends from the cutting edgeportion to define a length of relief. The depth of the length of reliefis a ratio to tool diameter of about 0.10 to 0.32 inches per inchdiameter of the tool. A method for boring a hole into concrete,aggregate or the like material is disclosed using the above cuttingtool. The cutting edge of the cutting tool is placed in contact with theaggregate. The cutting tool is rotated to bore the material. Due to theboring, a hole is formed in the material. Alternatively, instead ofrotating the tool, the tool may be impacted to chisel away the materialto form the hole. Optionally both boring and impacting may be conductedsimultaneously.

[0016] In accordance with a seventh aspect of the invention, a cuttingtool comprises a longitudinally extending shank portion which defines alongitudinal axis and two ends. One end has a chucking part and theother end has a cutting head. A press powdered metal cutting insert issecured on the cutting head. A cutting edge is on the cutting insert andincludes at least one cutting portion. A rake surface is formed, duringpressing of the powder, adjacent to at least one of the cuttingportions. Also, a clearance face is formed adjacent to the at least onecutting portion opposite the rake face. An edge radius is formed betweenthe rake face and the clearance face and has a radius of from about0.0015 to 0.004 inch. Likewise, a method of boring a hole in concreteaggregate or the like material is disclosed using the above cuttingtool. The cutting edge of the cutting tool is placed in contact with theconcrete aggregate or the like material. The cutting tool is rotated tobore the material. Due to the boring, a hole is formed in the material.Alternatively, instead of rotating the tool, the tool may be impacted tochisel away the material to form the hole. Optionally, both boring andimpacting may be conducted simultaneously.

[0017] In accordance with an eighth aspect of the invention, a cuttingtool includes a longitudinally extending shank with a chucking end and acutting head. A cutting insert is secured in the cutting head. A cuttingedge is formed in the cutting insert with at least one cutting edgeportion. A rake surface is formed, during the powder pressing process,adjacent to at least one of the cutting edge portions with the rake faceat an angle from 0° to about 10°. A method for boring a hole inconcrete, aggregate or the like materials disclosed using the abovecutting tool. The cutting edge of the cutting tool is placed in contactwith the material. The cutting tool is rotated to bore the material. Dueto the boring, a hole is formed in the material. Alternatively, insteadof rotating the tool, the tool may be impacted to chisel away thematerial to form the hole. Optionally, both boring and impacting may beconducted simultaneously.

[0018] In accordance with a ninth aspect of the invention, an insert isformed by a press powdered metal operation. A mold is provided with aninsert cavity which defines a longitudinal axis and has an opening alongthe longitudinal axis. Powdered metal material is added into the mold.The powdered metal material is compressed in the direction of thelongitudinal axis to form the insert. The method forms inserts like thatdescribed in the seventh and eight aspects. The method includes aV-shaped punch to compress the powdered metal material. Also duringcompressing of the insert, a land is formed on the face of the insert.The land is at an acute angle and counter clockwise with respect to theaxis of the insert. The land and the rake face may be joined in aradius.

[0019] Additional objects and advantages of the invention will beapparent from the detailed description of the preferred embodiment, theappended claims and the accompanying drawings, or may be learned bypractice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate two embodiments ofthe present invention and together, with the description, serve toexplain the principles of the invention. In the drawings, the samereference numeral indicates the same parts.

[0021]FIG. 1 is a perspective view of a prior art cutting tool.

[0022]FIG. 2 is a side plan view of the cutting tool of Figure 1.

[0023]FIG. 3 is a side plan view, rotated 900, of the cutting tool ofFIG. 1.

[0024]FIG. 4 is a top plan view of the cutting tool of FIG. 1.

[0025]FIG. 5 is an auxiliary view along the cutting edge of the cuttingtool of FIG. 2 illustrating the rake surface.

[0026]FIG. 6 is a perspective view of another prior art cutting tool.

[0027]FIG. 7 is a side plan view of the cutting tool of FIG. 6.

[0028]FIG. 8 is a side plan view, rotated 90°, of the cutting tool ofFIG. 6.

[0029]FIG. 9 is a top plan view of the cutting tool of FIG. 6.

[0030]FIG. 10 is an auxiliary view along the cutting edge of the cuttingtool of FIG. 7 illustrating the rake surface.

[0031]FIG. 11 is an enlarged side plan view of a cutting radius of FIGS.5 and 10 in circle 11.

[0032]FIG. 12 is a perspective view of a cutting tool in accordance withthe present invention.

[0033]FIG. 13 is a side plan view of the cutting tool of FIG. 12.

[0034]FIG. 14 is a side plan view, rotated 90°, of the cutting tool ofFIG. 12.

[0035]FIG. 15 is a top plan view of the cutting tool of FIG. 12.

[0036]FIG. 16 is an auxiliary view along the cutting edge of the cuttingtool of FIG. 12 illustrating the rake surface.

[0037]FIG. 17 is a perspective view of an alternate embodiment of thepresent invention.

[0038]FIG. 18 is a side plan view of the cutting tool of FIG. 17.

[0039]FIG. 19 is a side plan view, rotated 90°, of the cutting tool ofFIG. 17.

[0040]FIG. 20 is a top plan view of the cutting tool of FIG. 17.

[0041]FIG. 21 is an auxiliary view along the cutting edge of the cuttingtool of FIG. 17 illustrating the rake surface.

[0042]FIG. 22 is an enlarged view of the edge radius of FIGS. 16 and 21within circle 22.

[0043]FIG. 23 is a side plan view, partially in section, of the cuttingtool of FIG. 12 rotating within a material.

[0044]FIG. 24 is a view like FIG. 23 with the cutting tool impacting orchiseling the material.

[0045]FIG. 25 is a partial cross section of a side plan view of thecutting tool of FIG. 17 in the material during rotary boring.

[0046]FIG. 26 is a figure like that of FIG. 25 with the cutting toolimpacting or chiseling the material.

[0047]FIG. 27 is a figure like that of FIG. 25 with the cutting toolrotating and impacting or chiseling the material.

[0048]FIG. 28 is an auxiliary view along the cutting edge of a cuttingtool of an alternate embodiment illustrating an arcuate first egresssurface and area.

[0049]FIG. 29 is a side plan view of another embodiment of a cuttingtool with a 180° included angle.

[0050]FIG. 30 is a side plan view like FIG. 29 rotated 90°.

[0051]FIG. 31 is a perspective view of an alternate embodiment of thepresent invention.

[0052]FIG. 32 is a side plan view of the cutting tool of FIG. 31.

[0053]FIG. 33 is a side plan view, rotated 90°, of the cutting tool ofFIG. 31.

[0054]FIG. 34 is an auxiliary view along the cutting edge of the cuttingtool of FIG. 31 illustrating the rake surface.

[0055]FIG. 35 is a top plan view of the cutting tool of FIG. 31.

[0056]FIG. 36 is an enlarged view of the edge radius of FIG. 34.

[0057]FIG. 37 is an enlarged auxiliary view like that of FIG. 34.

[0058]FIG. 38 is a plan view of an insert in accordance with the presentinvention.

[0059]FIG. 39 is a schematic elevation view of a mold in accordance withthe invention.

[0060]FIG. 40 is a section view along line 40-40 of FIG. 39.

[0061]FIG. 41 is a section view along line 41-41 of FIG. 39.

DESCRIPTION OF PRIOR ART DRAWINGS

[0062] Turning to FIGS. 1 through 11, two prior art cutting tools areillustrated. FIGS. 1 through 5 illustrate a ball head single flutecutting tool, while FIGS. 6 through 10 illustrate a double helix cuttingtool. FIG. 11 illustrates the edge radius of both the cutting tools.

[0063] The ball head single helix cutting tool is designated with thereference numeral 100 and the double helix reference tool is designatedwith the reference numeral 102. The single flute cutting tool 100 has achucking end 104 for a hammer driver and a ball cutting head 106. Theshank 108 has the single helix 110 defining a flute 112. The flute 112ends at the cutting head 106 at a debris channel 114. Also, anadditional debris channel 116 is on the opposing side of the head, whichdumps directly into the flute 112, as seen in FIG. 3.

[0064] The cutting head 106 includes an insert 118, which includes acutting edge 120, either brazed or welded or the like into a slot 122 inthe cutting head 106. The insert is formed by placing powdered carbideinto a mold and compressing it. The insert is directly welded or brazedas described.

[0065] The cutting edge 120 is defined by rake faces 124, edge radius125, and clearance faces 126. Ordinarily, first egress faces 128 aredirectly adjacent to the rake faces and egress area 129 forms theremainder of the egress portion. The egress area 129 may be on the sameangle as the rake faces 124. The rake angle is negative and is about−30° to about −40°. The egress faces 128 lead into the debris channel114, 116. The rake faces 124 have a substantial negative rake angle withthe exception of some percussive bits which are at 0°. The edge radius125, as can best be seen in FIG. 11, is between the rake faces 124 andclearance faces 126 and, as can be seen, is relatively dull and is onthe order of 0.004 to 0.008 inch as measured on some prior art examples.However, in rotary only bits, while these bits may have 0° rake angles,the edge radius is in the mentioned range. Also, the rake face 124 andclearance face 126 define a cutting angle between the two surfaces. Thecutting angle is important for chiseling action and is about 45° to110°. Thus, with the negative rake angle and the dull edge radius, thecutting tool 100, 102, as it rotates, glides inside the hole, synonymousto spreading butter with a knife, smoothing away debris within the hole.This requires substantial force to initiate cutting of the hole in theconcrete, aggregate or the like material.

[0066] In the double helix cutting tool 102, the chucking end 104′ isdifferent from that of the single flute cutting tool 100 to illustrate arotary or percussive type chucking end. The tool includes helixes 111and 113 as well as flutes 115 and 117. As the flutes end at the cuttinghead 106, the debris channels 114 and 116 are formed at the end of eachof the flutes.

[0067] The cutting tip insert 118 is the same as that previouslydescribed and the rake faces 124, cutting edge 120, clearance surfaces126 and first egress surface 128′ and egress area 129′ are identifiedwith the same numbers. However, the egress area 129′ is different thanthat in the single flute design. Here, the egress area is parallel tothe rake face. Also, the debris channels 114′, 116′ are substantiallyidentical.

[0068] Both of these cutting tools illustrate a cutting tip having alarge obtuse included angle between the two cutting edges on the orderof 120° to 130°. Also, the egress angle, ordinarily about 30° to 35°,defining the plane of the egress area is relatively shallow. Likewise,the clearance angle, ordinarily about 20° to 30°, which defines theplane of the clearance surface is also shallow. Also a cutting angle,between the rake face and clearance face, is ordinarily about 90 to 110.

[0069] When defining angle measurement, the angles are true angles. Trueangles are taken by defining a plane parallel to the center line of thetool and through the cutting edge in an auxiliary view with the cuttingedge as a point. See FIGS. 5, 10, 16, 21. The rake angle, designated byα, is the angle measured from the defined plane to the rake face. Theclearance angle, designated by CA, is the complement of the anglemeasured from the defined plane to the clearance face. The cuttingangle, designated by β, is the angle between the clearance face and rakeface. The cutting angle β is equal to α+(90−CA). The egress angle,designated by λ, is the angle from the defined plane to the egress face.Positive rake angles are defined by clockwise rotation from a point onthe defined plane at the cutting edge to the rake face, when viewedalong the cutting edge from the outside diameter of the bit. Negativerake angles are defined by counterclockwise rotation from a point on thedefined plane at the cutting edge to the rake face, when viewed alongthe cutting edge from the outside diameter of the bit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0070] Turning to FIGS. 12 through 26, embodiments of the presentinvention are shown. FIGS. 12 through 16 illustrate a single helixdesign, designated with the reference numeral 200, and FIGS. 17 through21 illustrate a double helix design, designated with the referencenumeral 300, respectively.

[0071] The single helix cutting tool 200 includes a chucking end 204, inthis particular case illustrated as a spline for a hammer driver,however, a percussive and/or a cylindrical rotary end or otherattachment and drive means could be used. A cutting head 206 is at theother end of the cutting tool 200 and a shank 208 is between the twoends. The helix 210 defines a flute 212. The flute 212 ends at thecutting head 206 into a debris channel or recess 214. Likewise, a seconddebris channel or recess 216 is cut into the cutting head 206 opposingthe recess 214.

[0072] The cutting head 206 includes an insert 218 which includescutting edge 220, rake faces 224, and clearance faces 226. Likewise,egress faces 228 are immediately adjacent the rake faces 224.

[0073] The insert 218 has an overall pentagonal shape of a house withthe cutting edge 220 defining the roof, sides 230 and 232, and a base234 which is substantially perpendicular to the two parallel sides 230and 232. Also, the cutting edge could be along a straight line toprovide a rectangular insert, as seen in FIG. 29 and 30. Herecorresponding reference numerals are increased by 200. Thus, the cuttingtool is designated with the reference numeral 400. The insert 218 isbrazed, welded or the like into the slot 222 in the cutting head 206.The insert 218 is generally manufactured from a carbide material, suchas carbide or tungsten carbide, however, ceramics, ceramic composites,diamond dust, metal ceramic composites or a unitary homogeneous or adeposit of layers could be used. Also, the entire cutting tool could bemanufactured from such material or a portion thereof, including the head206 manufactured from such a material, eliminating the insert 218.

[0074] The cutting edges 220 are defined by rake faces 224, edge radius240 and the clearance faces 226. The cutting edges 220 include a primarycutting edge 236 and a secondary cutting edge 238. The primary cuttingedge 236 is on an acute angle with respect to the longitudinal axis 242,while the secondary cutting edge 238 is substantially perpendicular tothe longitudinal axis 242.

[0075] The cutting edges 220 include edge radius 240 between the rakefaces 224 and clearance faces 226 (see FIG. 22). The edge radius 240defines the sharpness of the cutting tool. An edge radius 240 of thepresent invention is generally between 0.0003 to 0.004 and preferablybetween 0.0005 to 0.001. Having a desired edge radius 240 provides adesired sharpness to enable the cutting tool to cut through theconcrete, aggregate or the like material during rotation of the cuttingtool. The edge radius is formed by working, such as by grinding or thelike, the clearance face and the rake face.

[0076] The two cutting edges 220 form a tip or point 221 between them.The included angle (IA) between the two cutting edges 220 is from about90° to 180° and preferably about 100 to 160.

[0077] The cutting edges 220 are offset from the longitudinal axis 242of the cutting tool 200. The rake faces 224 are worked or ground intothe insert and define rake angles a as defined above. Generally, therake angle α is between 10° to −10°, preferably at about 0° for theprimary cutting edge portion 236. The rake angle is between −50° to −20°preferably −40° for the secondary cutting edge portion 238. Thus, theworked rake surfaces are substantially parallel to the longitudinal axis242.

[0078] The rake faces 224 are formed by working, such as grinding or thelike, into both sides of the insert 218 and extend a desired distancefrom the cutting edge 220. The distance or depth which the rake faces224, which are worked or ground into the insert, extend from the cuttingedge is known as the length of relief. The depth of the length of reliefis measured from the cutting edge 220 along the longitudinal axis 242 toa first egress surface 244. The length of relief of the rake faces 224has a depth of about 0.08 to about 0.25 inch for a ¾ inch diameter bit.Preferably, the depth is from about 0.15 to about 0.25 inch. The lengthof relief can be defined as a ratio with respect to the diameter of thetool. Thus, the length of relief ratio is about 0.10 to about 0.32inches per inch diameter of the tool.

[0079] The first egress surface 244 angles from the terminus or end ofthe length of relief. The first egress surface 244 is generally angledwith respect to the rake face 224, providing an overall stepped cuttinghead, as seen in FIGS. 16 and 21. The angle of the first egress surface244 is from about 30° to 90° and preferably 55° to 60° and may becontinuous with and at the same angle as the egress area 228.

[0080] The clearance surface 226, which includes a portion of the insert218 and the cutting head 206 define a clearance angle CA. The clearanceangle CA is defined as mentioned above. This clearance angle is fromabout 10° to about 50° and preferably about 20° to 40° for hammer andpercussive tools and 30° to 50° for rotary only tools.

[0081] A cutting angle β, as defined above, is defined between theclearance face 226 and rake face 224. The cutting angle β is from about30° to 90° and preferably from about 40° to 60° for the primary cuttingedge portion. The cutting angle for the secondary cutting edge portionvaries from 60° to 120° preferably from 80° to 100°. These cuttingangles define a primary cutting edge portion which enhances cuttingaction, while the cutting angle defined for the secondary cutting edgeportion enhances the chiseling action of the cutting tool.

[0082] The egress area 228 defines an egress angle λ which is measuredas mentioned above. The egress area 228 is adjacent to the first egresssurface 244. The angle is at least 0° and preferably from about 30° to60° for hammer and percussive tools and at about −20° to 90° for rotaryonly tools, preferably about −20° to 20° for hammer and percussive toolsand 45° to 105° for rotary only tools. Also, the first egress surface244′ and egress area 228′ may be arcuate as seen in FIG. 28. Here theyare shown on the same arc, however, they could be on different arcs.This egress angle and surface enhance the transport of debris from thetool tip into the flute 212 of the shank 208. Thus, by providing adesired egress angle, choking is prohibited at the cutting head 206. Asseen in FIGS. 12 through 16, a larger volume of material is removed fromthe ball head enabling better debris removal.

[0083] Turning to FIGS. 17 to 21, the double helix embodiment of thepresent invention is shown. The cutting tool 300 includes a chuck end304 which is a rotary or percussive type of cutting tool end. Also, thehelixes 307 and 309 and flutes 310 and 312 are different from thosepreviously described. The helixes 310 and 312 end at the cutting head306, thus enabling the debris recesses 314 and 316 to include a largervolume of debris. The remaining portions of the cutting head 306 aredesignated with reference numerals increased by a hundred and thedescription is the same as in the first embodiment since these elementsare the same. The difference in the head 306 in the egress area 328 andclearance surface 326 is due to a reduced amount of material present inthe double helix design than is present in the single helix design.Otherwise, the angle parameters previously described are the same withthe double helix design as they are with the single helix design.

[0084] Turning to FIGS. 23 through 27, the cutting tools of the presentinvention are illustrated in concrete, aggregate or the like material,boring a hole. When the terms concrete, aggregate or the like materialare used, the cutting tools may be used to bore, but are not limited to,cap block, brick, stone, ceramic materials, concrete, aggregate, blacktop, rock, cement, masonry or the like materials. In drilling a holeusing rotary only motion, the bit of the present invention contacts theconcrete, aggregate or the like material. The cutting tool may berotated only where the rake face of the cutting tool cuts and bores ahole into the material. Alternatively, the cutting tool contacts theconcrete, aggregate or the like material and impacts or chisels thematerial to form a hole. Further, the cutting tool may contact thematerial and impacting and rotating movement utilized together to bore ahole as seen in FIG. 27. Generally, the impacting is sequential andrepetitious so that a constant repeating force is applied onto thecutting tool. Also, when the cutting tool is purely rotational, aconstant force may be applied to the driver.

[0085]FIGS. 31 through 37 illustrate a double helix embodiment of thepresent invention. Cutting tool 500 includes a chuck end 504 which is arotary or percussive type of cutting tool end. Also, the helixes 507 and509 and the flutes 510 and 512 are like those previously described withrespect to FIGS. 17 through 21. The helixes 510 and 512 end at thecutting head 506, thus enabling the debris recesses 514 and 516 toinclude a larger volume of debris.

[0086] The cutting head 506 includes an insert 518 which includescutting edges 520, rake faces 524 and clearance faces 526. Likewise,egress faces 528 are immediately adjacent the rake face 524.

[0087] The insert 518 has an overall pentagonal shape of a house withthe cutting edge 520 defining the roof, sides 530 and 532, and a base534, which is substantially perpendicular to the two parallel sides 530and 532. Also the cutting edges 520 could be along a straight line toprovide a rectangular insert as seen in FIGS. 29 and 30.

[0088] The insert 518 is braised, welded or the like into the slot 522on the cutting head 506. The insert 518 is generally manufactured from acarbide material such as a cobalt carbide mixture however, ceramic,ceramic composites, diamond dust, metal ceramic composites or a unitaryhomogeneous or a deposit of layers could be used.

[0089] Cutting edges 520 are defined by rake faces 524, edge radii 540and clearance faces 526. The cutting edges 520 include a primary cuttingedge 536 and a secondary cutting edge 538. The primary cutting edge 536is on an acute angle with respect to a longitudinal axis 542, while thesecondary cutting edge 538 is substantially perpendicular to thelongitudinal axis 542. The cutting edges 520 include edge radius 540between the rake faces 524 and clearance faces 526 as seen in FIG. 36.

[0090] The edge radius 540 defines a sharpness of the cutting tool. Anedge radius 540 of the present invention is between 0.0015 to 0.004 andpreferably between 0.002 to 0.003. Having a desired edge radius 540provides a desired sharpness to enable the cutting tool to cut throughthe concrete, aggregate or the like material during rotation of thecutting tool. The edge radius as mentioned above is formed during thepowder pressing operation.

[0091] The included angle between the two cutting edges is like thosepreviously described. Also, the rake face angle α is between 10° and 0°preferably at about 5°. However, these angles are formed during thepressing operation. Also, the angles of the primary and secondarycutting edge are similar to those described above. The clearance angleCA as well as the cutting angle β are the same as those described above.

[0092] In this embodiment, a first egress surface is eliminated and anegress area 528 is defined by an egress angle λ which is measured asmentioned above. The egress area 528 is adjacent to the rake face 524.The angle is between 80° and 100° and is preferably about 90°.

[0093] For a better understanding of molding the insert, refer to FIG.38 through 41.

[0094] The insert 518 is illustrated with a clearance face 526, rakefaces 524 and a trailing face 525. The land 533 is formed between theclearance face 524 and the trailing face 525. The width (X) of the rakeface 524, at the bottom of the insert, along the base 534 is wider thanthe width (Y) of the trailing face 525 such that an angle B is formedalong the land 533 with respect to the central axis 559. The lineextending from the land 533 is on an angle which is counter clockwiseaway from the central axis. This angle enables the insert to be removedfrom the mold.

[0095] Turning to FIG. 39, a mold and punch is illustrated. A V-shapedpunch 560 forms the roof of the insert 518 and an ejector pin 562, inthe mold 564, ejects the insert after it has been molded. Powdered metalis poured into the mold 564 and the punch 560 is inserted compressingthe powder metal within the mold 564. Upon compressing the powderedmetal, as seen in FIG. 40, at the bottom of the mold 564, the portion568 of the mold 564 forming the rake face 524 extends inward from theportion 570 of the mold 564 that forms the trailing face 525. At the topof the mold 564, the width of the molds are substantially the same asseen in FIG. 41. Thus, when the insert 518 is ejected from the mold 564,since the bottom portion of the rake face 524 is in an area as it exitsthe mold which is wider than the rake face base portion of the insert518, the insert 518 is easily ejected from the mold 564. However, if theangle B was clockwise with respect to the central axis 559, the landwould be formed in the opposite direction and the insert would be jammedwithin the mold since the bottom of the insert would be wider than thewidth of the top of the mold.

[0096] By having the punch 560 move axially with respect to the insert,the desired rake faces 524 and clearance faces 526 as well as the edgeradii 540 are formed on the insert 518. The above identified insert 518forming is contrary to conventional molding of positive rake carbideinserts, which moves a punch laterally or perpendicular to the axis ofthe insert, to form the insert.

[0097] To manufacture a cutting tool in accordance with the invention,ordinarily the tool would be made in methods consistent with those inthe art. To provide a tip with surfaces like those disclosed, ordinarilythe rake surfaces, egress surfaces and clearance surfaces would beground or formed by other conventional means into the cutting tool toform the desired surfaces with desired angles.

[0098] While the above detailed description describes the preferredembodiment of the present invention, the invention is susceptible tomodification, variation, and alteration without deviating from the scopeand fair meaning of the subjoined claims.

1. A cutting tool for boring concrete or the like material comprising: alongitudinally extending shank portion defining a longitudinal axishaving two ends; a chucking part provided at one end of the shankportion; a cutting head provided at the other end of said shank portion,a pressed powder cutting insert in said cutting head, a cutting edge onsaid cutting insert, said cutting edge having at least one cutting edgeportion, a rake face, formed during said pressing of said powder,adjacent said cutting edge, said rake face being at a rake angle fromabout 0° to about 10°.
 2. The cutting tool according to claim 1, whereinat least two cutting edge portions each include a rake surface.
 3. Thecutting tool according to claim 1, wherein said rake face angle ispreferably about 5°.
 4. The cutting tool according to claim 1, whereinsaid rake face angle is positive.
 5. A cutting tool for boring concreteor the like material comprising: a longitudinally extending shankportion defining a longitudinal axis and having two ends; a chuckingpart provided at one end of the shank portion; a cutting head providedat the other end of said shank portion, a pressed powder cutting inserton said cutting head, a cutting edge on said cutting insert, saidcutting edge including at least one cutting edge portion, a rake faceformed adjacent said at least one cutting portion, a clearance faceformed adjacent said at least one cutting portion opposing said rakeface, said rake face and clearance face formed during pressing of thepowder, and an edge radius between said rake face and clearance face,said edge radius having a radius of about 0.0015 to 0.004 inch.
 6. Thecutting tool according to claim 11, including at least two cutting edgeportions, both cutting edge portions include a rake surface.
 7. Thecutting tool according to claim 5, wherein said clearance face is at anangle of about 30° to about 40°.
 8. The cutting tool according to claim5, wherein said edge radius is preferably from about 0.002 to about0.003.
 9. The cutting tool according to claim 5, wherein an egress faceis adjacent said rake face.
 10. The cutting tool according to claim 9,wherein said egress face is at an angle of about 80° to about 100°. 11.The cutting tool according to claim 10, wherein said egress face is atan angle of about 90°.
 12. A cutting tool for concrete, aggregate or thelike material comprising: a longitudinally extending shank portiondefining a longitudinal axis and having two ends; a chucking partprovided at one end of the shank portion; a cutting head provided at theother end of said shank portion, a pressed powder cutting insert in saidcutting head, a cutting edge formed on said cutting insert, said cuttingedge having at least one cutting edge portion, a rake surface formedadjacent said cutting edge during pressing of the powder, said rakesurface being at a positive rake angle.
 13. A method of boring a hole inconcrete, aggregate or the like material comprising: providing a cuttingtool including a longitudinally extending shank portion defining alongitudinal axis and having two ends, a chucking part provided at oneend of the shank portion, a cutting head provided at the other end ofsaid shank portion, a pressed powder cutting insert in said cuttinghead, a cutting edge on said cutting insert, said cutting edge having atleast one cutting edge portion, a rake surface formed adjacent saidcutting edge portion, said rake face being at a rake angle from about 0°to about 10°; contacting said cutting edge with the material; rotatingsaid cutting tool to cut said material; and forming a hole in saidmaterial.
 14. The method of claim 13, including applying a force alongsaid longitudinal axis of said cutting tool.
 15. The method of claim 14,wherein said force is constant.
 16. The method of claim 14, wherein saidforce is sequentially repetitious to impact the material to chisel thematerial.
 17. A method of boring a hole in concrete, aggregate or thelike material comprising: providing a cutting tool including alongitudinally extending shank portion defining a longitudinal axis andhaving two ends, a chucking part provided at one end of the shankportion, a cutting head provided at the other end of said shank portion,a pressed powder cutting insert in said cutting head, a cutting edge onsaid cutting insert, said cutting edge having at least one cutting edgeportion, a rake surface formed adjacent said cutting edge portion, saidrake face being at a rake angle from about 0° to about 10°; contactingsaid cutting edge with the material; impacting said cutting tool tochisel said material; and forming a hole in said material.
 18. Themethod of claim 17, including rotating said cutting tool to cut thematerial.
 19. A method of boring a hole in concrete, aggregate or thelike material comprising: providing a cutting tool including alongitudinally extending shank portion defining a longitudinal axis andhaving two ends, a chucking part provided at one end of the shankportion, a cutting head provided at the other end of said shank portion,a pressed powder cutting insert in said cutting head, a cutting edge onsaid cutting insert, said cutting edge including at least one cuttingedge portion, a rake surface formed adjacent said at least one cuttingportion, a clearance face formed adjacent said at least one cuttingportion opposing said rake face, and an edge radius between said rakeface and clearance face, said edge radius of from about 0.0015 to 0.004inch; contacting said cutting edge with the material; rotating saidcutting tool to cut said material; and forming a hole in said material.20. The method of claim 19, including applying a force along saidlongitudinal axis of said cutting tool.
 21. The method of claim 20,wherein said force is constant.
 22. The method of claim 21, wherein saidforce is sequentially repetitious to impact the material to chisel thematerial.
 23. A method of boring a hole in concrete, aggregate or thelike material comprising: providing a cutting tool including alongitudinally extending shank portion defining a longitudinal axis andhaving two ends, a chucking part provided at one end of the shankportion, a cutting head provided at the other end of said shank portion,a pressed powder cutting insert in said cutting head, a cutting edge onsaid cutting insert, said cutting edge including at least one cuttingedge portion, a rake surface formed adjacent said at least one cuttingportion, a clearance face formed adjacent said at least one cuttingportion opposing said rake face, and an edge radius between said rakeface and clearance face, said edge radius having a radius of from about0.0015 to 0.004 inch; contacting said cutting edge with the material;impacting said cutting tool to chisel said material; and forming a holein said material.
 24. The method of claim 23, including rotating saidcutting tool to cut the material.
 25. A method of forming an insertcomprising: providing a mold with an insert cavity defining alongitudinal axis and having an opening along the longitudinal axis;adding powder material into the mold; compressing the material in thedirection of the longitudinal axis; forming the insert with a positiverake face.
 26. The method of forming an insert according to claim 25further comprising a V-shaped punch compressing said powder material.27. The method of forming an insert according to claim 25 and forming aland on a face of said insert, said land being at an acute angle andcounter clockwise with respect to an axis of the insert.
 28. The methodof forming an insert according to claim 25, wherein said insert has adesired rake face, clearance face and edge radius.
 29. The method offorming an insert according to claim 25 and ejecting the insert from themold.